U-Pb zircon age data for supracrustal samples from the White Hills Lake to Amer Lake area, Rae Province, Nunavut, Canada

2021 ◽  
Author(s):  
W J Davis
Keyword(s):  
Lake Area ◽  
Zircon Age

Rubidium–strontium age and origin of uraniferous granite, Molson Lake – Red Sucker Lake area, northwestern Superior Province, Manitoba

1987 ◽  
Vol 24 (3) ◽  
pp. 471-478 ◽  
Author(s):  
G. S. Clark ◽  
W. Weber
Keyword(s):  
Granulite Facies ◽  
Lake Area ◽  
Initial Ratio ◽  
Calc Alkaline ◽  
Small Bodies ◽  
Zircon Age ◽  
Granulite Facies Metamorphism ◽  
The World ◽  
Facies Metamorphism ◽  
Data Points

Late Archean, post-kinematic, uraniferous granite and alaskite occur as several discrete large and small bodies in the 250 km long Molson Lake – Red Sucker Lake batholithic belt, in the western Gods Lake subprovince. Sampled over this length, this unit gave a Rb–Sr whole-rock age of 2495 ± 30 Ma with an initial 87Sr/86Sr ratio of 0.7053 ± 0.0023. The excellent fit of the data points suggest a common, isotopically homogeneous source of magma for the analyzed granite bodies. The initial ratio is consistent with an origin from partial melting of older calc-alkaline rocks, and evidence suggests this event accompanied granulite-facies metamorphism. Based on recent U–Pb zircon ages, this event could have occurred as much as 200 Ma prior to closure of the Rb–Sr isotopic system.An older, monzonite–quartz diorite unit gives a less well-defined age of 2690 Ma, consistent with a U–Pb zircon age from the same unit. This pluton is intrusive into older, tonalitic gneisses and is part of a widespread suite of granitoid plutonic rocks in this subprovince. This pluton gives a low, mantle-like initial ratio, indicating juvenile additions to the crust during this period of batholithic development, consistent with findings for calc-alkaline granitoids in Archean shield areas elsewhere in the world.

The paleomagnetic significance of new U-Pb age data from the Molson dyke swarm, Cauchon Lake area, Manitoba

2000 ◽  
Vol 37 (6) ◽  
pp. 957-966 ◽  
Author(s):  
Henry C Halls ◽  
Larry M Heaman
Keyword(s):  
Opposite Polarity ◽  
Sensu Stricto ◽  
Dyke Swarm ◽  
Lake Area ◽  
Continental Rifting ◽  
Zircon Age ◽  
Western Margin ◽  
Back Arc ◽  
Superior Craton ◽  
Age Determinations

U-Pb geochronology, paleomagnetism, and petrography indicate that the Molson dyke swarm, along the western margin of the Superior craton, is a composite of at least two ages of intrusion. The more extensive younger dyke set, the Molson swarm sensu stricto, generally has a 030° trend, is mainly pyroxenitic to noritic with subordinate diabase, and has been related to rifting in a back-arc environment during closure of the Manikewan ocean at about 1920-1800 Ma which culminated in the Trans-Hudson Orogen. A U-Pb zircon age from one of these dykes, located at Cauchon Lake, indicates emplacement at 1877+7&#150 4, similar to two previous U-Pb age determinations on Molson dykes. Another dyke from Cauchon Lake yields a baddeleyite-zircon U-Pb date of 2091 ± 2 Ma and appears to be part of an older, mainly diabasic suite of east-northeast-trending dykes that may represent a continental rifting episode that preceded the opening of the Manikewan ocean. The new U-Pb age data require a revision to the interpretation of the A, B, and C paleomagnetic poles previously reported from Molson dykes. The A pole (16.1°N, 96.5°W), initially assigned an age of 1883 Ma, is now considered to be younger and derived from a Paleoproterozoic overprint associated with the Trans-Hudson Orogen at about 1700-1800 Ma. Pole B (27.1°N, 140.8°W) from the Molson swarm sensu stricto is now regarded as primary, and dated at 1880 Ma. Pole C can be subdivided into two poles, one virtually the same as B but of opposite polarity (and therefore about 1880 Ma old) and a new pole (53°N, 180°W) derived from a primary remanence and dated at 2091 Ma. The new paleomagnetic interpretations may have important consequences for tectonic models of the Trans-Hudson Orogen and for Paleoproterozoic continental reconstructions.

U-Pb zircon age and geochemistry of the Bl fjellhatten granite, Grong-Olden Culmination, Central Norway

1999 ◽  
Vol 79 (3) ◽  
pp. 161-168 ◽  
Author(s):  
David Roberts ◽  
August L. Nissen ◽  
Nicholas Walker
Keyword(s):  
Zircon Age
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